The polymerization of hexaorganocyclotrisiloxane in the presence of catalytic amounts of a pentacoordinated silicon catalyst, an alkali metal siliconate, ammonium siliconate or phosphonium siliconate and at least traces of a sil(ox)anol is known from U.S. Pat. No. 3,445,426 (corresponds to DE-B 1 720 496). However, the catalyst is not readily available and is sensitive to moisture.
The polymerization of hexaorganocyclotrisiloxanes in the presence of sil(ox)anols and with the aid of alkali metal sil(ox)anolates as polymerization initiators is described in EP-A 331 753. Alkali metal sil(ox)anolates also have a sensitivity to moisture.
The polymerization of hexamethylcyclotrisiloxane in the presence of trialkylsilanol and a lithium catalyst, such as butyllithium, is known from EP-A 338 577. The use of organometallic compounds presents safety problems.
The ring-opening and polymerization of cyclic siloxanes in the presence of fluoride ions is described in L. M. Tartakovskaya et al., Vysokomol, Soedin, Ser. B 26, 234, 1984 (Chemical Abstracts Volume 101, 73186d, 1984).
Therefore, it is an object of the present invention to provide a process for preparing organo(poly)siloxanes, which avoids the disadvantages mentioned above. Another object of the present invention is to provide a process for preparing organo(poly)siloxanes which uses a catalyst that is readily available and is easy to handle.